Find the single discount equivalent to two successive discounts of $20\%$ and $10\%$.

Rajan bought a watch for $₹1870$ including VAT at $10\%$. Find the original price of the watch.

On selling $100$ pens, a man gains a selling price of $20$ pens. The gain percent is

A man sells a bat for $₹100$ gaining $₹20$. His gain percent is

A dealer lists his goods at $20\%$ above the cost price and allows a discount of $10\%$. His gain percent is

The discount is reckoned on the _____ price.